Usage of variable in xslt (Data Transformation)

We use XSLT in data transformation and in one particular situation we might want to use same value for different fields. A variable in such case is a best approach one could think of. Below is the code snippet which is used in xslt in order to create and use a variable.

Below is a part of xslt which can be referred as an example,

<sch:ReceivedReturnCenter>
<xsl:value-of xmlns:sch="http://schemas.cordys.com/" select="concat(substring(/sch:ROConDTInput/sch:request/sch:GRDATE,7,2),substring(/sch:ROConDTInput/sch:request/sch:GRDATE,5,2),substring(/sch:ROConDTInput/sch:request/sch:GRDATE,1,4))" />
</sch:ReceivedReturnCenter>
<sch:SendBackToCustomer>
<xsl:value-of xmlns:sch="http://schemas.cordys.com/" select="concat(substring(/sch:ROConDTInput/sch:request/sch:GRDATE,7,2),substring(/sch:ROConDTInput/sch:request/sch:GRDATE,5,2),substring(/sch:ROConDTInput/sch:request/sch:GRDATE,1,4))" />
</sch:SendBackToCustomer>

Here both the target values "ReceivedReturnCenter" and "SendBackToCustomer" are mapped to a single value which is concatenation/substring of another field "GRDATE".

No doubt with this approach we would achieve the solution but its unnecessary to perform the same logic multiple times. Hence ideally we would be having the logic stored in a variable and use that variable to assign to both the target fields. Here is how we can do it,

<xsl:variable name="grDate">
<xsl:value-of xmlns:sch="http://schemas.cordys.com/" select="concat(substring(/sch:ROConDTInput/sch:request/sch:GRDATE,7,2),substring(/sch:ROConDTInput/sch:request/sch:GRDATE,5,2),substring(/sch:ROConDTInput/sch:request/sch:GRDATE,1,4))" />
</xsl:variable>
<sch:ReceivedReturnCenter>
<xsl:value-of select="$grDate" />
</sch:ReceivedReturnCenter>
<sch:SendBackToCustomer>
<xsl:value-of select="$grDate" />
</sch:SendBackToCustomer>

Usage of variable : $grDate

Note : There is a drawback of using variable in xslt as the same variable cannot be edited later (or I am not aware of :P). Variables in xslt are supposed to be initialized/assigned a value only once.